Fatty aldehydes produced from tallow, coconut oil, palm oil etc. as the starting material are important intermediates in household and industrial fields, and are utilized in a wide variety of applications such as the field of perfume.
Conventionally, there is a method of producing an aldehyde from an alcohol as the starting material by dehydrogenation reaction or oxidation reaction. For example, JP-B 7-34865 discloses a method of preparing a target carbonyl compound (aldehyde or ketone) through dehydrogenation reaction by using a Cu/Fe/Al/(alkali metal and/or alkaline earth metal)/Zn catalyst. When such a catalyst is used, the product can be obtained with a high selectivity. But any technique such as stirring for effectively mixing the starting materials with the catalyst is required because of a suspended bed system using such a powdery catalyst. The product should be separated, for example, by filtration from the catalyst. Such problems make facilities and operations complicated.
On the other hand, a fixed bed system can be mentioned as a process neither requiring the operation of mixing the catalyst by stirring or gas bubbling nor necessitating separation by filtration.
As one form of the catalyst used in a fixed bed system, a pellet-, noodle- or tablet-shaped molded catalyst has been well known. A catalytically active substance in a powdery form can be molded into the above form by a method such as compression or extrusion, to form a structure having numberless pores thereby attaining a bulk form and high surface area simultaneously.
As another form of the catalyst used in a fixed bed system, a honeycomb-shaped catalyst is known. JP-B 62-21574 discloses a catalyst in the form of a structure having a large number of flow paths in the direction of from the inlet to outlet of a fluid, which are separated from one another by a thin wall, for example a pipe, a honeycomb, a plate or the like.